There are distance measuring apps out there, but measuring the diameter of a pipe presents a unique measuring situation.
- Calibration. There will need to be some way of checking to see if the app is working correctly. You will need to measure a known standard to see if the app is measuring right. If not, there needs to be some way of calibrating or adjusting the reading, to make it accurate. In other words, if you measure a 2 inch pipe, and the app says 2.1 inches, you need a way to adjust the setting to read 2.0 inches. Otherwise, when you measure a 3 inch pipe or any size pipe, the measurement would be off.
- Calibration should be done with different sizes of pipe, to make sure you will get an accurate reading at any of those sizes.
- The curvature of the pipe needs to be considered. You aren’t taking a picture of a 2D object. The pipe is 3D, so your camera may not see the top and bottom of the pipe as being 180 degrees away from each other. If you are too close to the pipe, you wouldn’t see the full 180 degrees. So your measurement would be too small.
- Resolution of measuring. A pipe diameter tape measure normally has a resolution of 100th of an inch diameter. Can a smart phone app be that accurate?
- The nearness of the object. For calibration, we would need some standard distance from the cell phone. Maybe this could be accomplished by using an object like a 12″ ruler, placed between the pipe and the phone. Hopefully, a less mechanical method will pop up.
If you know of an app that can accurately measure pipe diameter, please let me know. If one does not exist, I’m sure it will be invented in the near future.